Athens (AFP) - Greek Prime Minister Alexis Tsipras on Monday prepared for a confidence vote on his government this week after his nationalist ally resigned in a row over a name change deal with neighbouring Macedonia.

Tsipras called for the vote in parliament following the Sunday resignation of defence minister Panos Kammenos, leader of the small nationalist ANEL party, after four years in coalition government.

Kammenos' departure raises the possibility of snap elections, though government spokesman Dimitris Tzanakopoulos said Monday the administration could still see its four-year term through to October.

"I believe the government will win the vote and will be able to...complete its (term)," Tzanakopoulos told Alpha TV, admitting that Tsipras' move was "high-risk".

Parliament speaker Nikos Voutsis has said the debate over the confidence motion will start on Tuesday, with a vote likely on Wednesday night.

"The current situation requires compromise and unity," Apostolakis told journalists before a meeting with Tsipras.

As well as the confidence vote on the government, parliament will also vote on whether to support the Macedonia deal, but no date has been set for that ballot.

Greek resistence

Tsipras' leftist Syriza party has 145 deputies in the 300-member Greek Parliament but could win the confidence vote with just 120 votes if enough lawmakers abstain.

The Macedonia deal requires at least 151 votes. A number of independent deputies have pledged their support, enough to secure its approval.

Kammenos' ANEL party is fervently opposed to the proposed deal with Macedonia to end a 27-year dispute over the country's name.

Earlier Monday he kicked out two MPs who voiced support for Tsipras, reducing his parliamentary group to five.

Macedonian lawmakers voted on Friday to rename their country the Republic of North Macedonia but the agreement will only come into effect with backing from the Greek parliament.

The proposal faces resistance in Greece, which has a northern province of the same name just across the border, over implied claims to Greek land and cultural heritage.

For most Greeks, Macedonia is the name of their history-rich northern province made famous by Alexander the Great's conquests.

The European Union and NATO have hailed the deal, which will lift Greek objections to Macedonia joining both organisations.

German Chancellor Angela Merkel, who was visiting Greece on Thursday, said she was "grateful" to Tsipras for brokering the deal over strong opposition in both countries.

The agreement "will benefit North Macedonia, Greece and the European Union. I strongly believe that," she said according to the official translation.

European Commission spokeswoman Maja Kocijancic told reporters in Brussels earlier Monday that the bloc backed the deal, saying it had taken "political courage" to resolve one of the region's oldest conflicts.

"We see it as the unique opportunity to overcome the difficulties of the past, to enhance reconciliation for the region and for Europe as a whole," she said. "We are now following the national procedures that are needed for the implementation of this agreement."